The present invention relates to an electric steam iron for domestic use.
Known electric steam irons mainly comprise a housing, a water tank, a bottom plate and a heating device which is used to heat the bottom plate. A boiling chamber is provided inside the bottom plate, whereby the water can be heated up and boiled by the bottom plate, so that the boiling chamber in the bottom plate forms a steam generator. When the iron is working, the water in the boiling chamber is heated by the bottom plate and turns to steam, and this can then be sprayed out from the steam outlet of the bottom plate to iron the clothing. However, since all the heat to boil the water is supplied by the bottom plate which is also used as the ironing part, the temperature of the bottom plate cannot be so high during the ironing operation, and in addition, the temperature will therefore sometimes decrease when the bottom plate contacts outside objects, both of which will result in part of the steam changing into water drops, which have an impact on the ironing effect. Therefore, some new irons with independent steam generators relative to the bottom plate have been provided to solve this problem. For example, Chinese Patent Application No. 02152250.2, entitled “A Bottom Plate on the Steam Iron for Home Use,” is an example of such technology. The steam iron in that invention comprises a bottom plate, a heating device to heat the bottom plate, a temperature controller on the surface of the bottom plate and an independent steam generator above the bottom plate, and the steam generator includes an independent boiling chamber, a heating device to heat the boiling chamber and a temperature controller on the surface of the boiling chamber. The inlet of the boiling chamber communicates with the water tank, and the outlet of the boiling chamber communicates with the outlet opening in the bottom plate.
The known electric steam iron generally includes only one heating circuit to provide power to the heating device on the bottom plate, and includes only two switches. One switch is used to control the entire operation of the iron, that is, the power switch which provides power to the heating device in the bottom plate, and which is also a knob switch that is united with the adjusting switch of the temperature controller of the bottom plate, whereby the latter switch can select the corresponding temperature according to the material of the clothing that needs to be ironed. The other switch is used to control exhausting of steam. In operation, once the power switch of the electric iron is turned off, the boiling chamber inside the bottom plate will cool down, and it is necessary for the cool boiling chamber to be heated again in order for the steam generator to restart to work. Then the heating device should warm up the boiling chamber. However, this will cost a lot of time. Therefore, when the user needs to iron a passel of clothes, the electric iron is in a discontinuous state of use. It is therefore power-consuming to turn on the switch all the time, and it is time-consuming to turn off the switch when not in use, since time is needed to warm up the boiling chamber. Therefore, this arrangement is not suitable for practical use.
Regarding the electric steam iron of the Chinese patent mentioned above, if both the independent steam generator and the heating device in the bottom plate are powered and controlled by the same heating circuit, this will not be suitable for use either since it will produce the same problems as the existing electric steam iron.